Now, assuming that we trust the government-- I think the U.S. Government has never defaulted on its debt-- we'd take that as a riskless return.

假设我们信任政府-,假设美国政府从未拖欠债务-,可以把它当作无风险回报。

耶鲁公开课 - 金融市场课程节选

But then the U.S. crashed into a huge well actually it was as worldwide recession of 1981-2.This was the biggest recession since The Great Depression.

但是之后，美国卷进了一个巨大的,事实上，是个世界范围内的经济衰退,于1981-1982年，这是自从大萧条以来,最严重的一次经济衰退。

耶鲁公开课 - 金融市场课程节选

So let's -- we'll go to a brand new color, TS define A as u minus TS.

我们用一种新的颜色，定义A等于u减去。

麻省理工公开课 - 热力学与动力学课程节选